Numerous industrial processes produce waste material in the form of a sludge which is composed of a liquid and at least one solid that must be separated for disposal or recovery of the components. Examples of such waste material include waste from animal or vegetal agri-food industries, manure, industrial sludge from fabrication processes of various products, used water, wet contaminated soil, etc. Typically, the liquid is separated from the solid using a filter which will retain the solid and let the liquid pass through. Generally, the fluid can be drawn through the filter either by gravity or by the use of a vacuum produced by a pump.
There exists a number of filter assemblies located within a mobile box, with a free space in the box around the filter assembly for receiving the liquid, such as is described in U.S. Pat. Nos. 4,929,353 and 6,004,461, both to Harris, and U.S. Pat. No. 6,258,268 to Lake. Although such assemblies rely on gravity to extract the liquid from the sludge through the filter bed, the side filters, which are vertical, rely mainly on capillary action to force the liquid therethrough, which is slower and less efficient.
In addition, the systems presented in these patents usually require the change of filter material and/or mesh size when the nature of the material to be filtered is changed, thus preventing the manufacture of standard filter panels than can be employed with a variety of materials to be filtered.
Accordingly, there is a need for a mobile gravitational filtration system with increased efficiency, which can use standard filter panels for a variety of materials to be filtered.